Effect of Microalgae Growth Promoting Bacteria on Biomass Production of Scenedesmus Isolates in Co-Culture Systems

Microalgae are biotechnologically important microorganisms with the potential to address the challenges posed by rapid population growth and dwindling food resources through their metabolic products. This study focused on the isolation and identification of Scenedesmus and microalgae growth-promoting bacteria (MGPB) from wetlands in Erzurum, Türkiye, and investigated the impact of MGPB isolates on the growth performance of Scenedesmus species in a co-culture medium. Scenedesmus and MGPB isolates were collected from Palandoken Teke Creek Pond and Tortum Lake, respectively, followed by species identification. Co-culture experiments were conducted using 20 MGPB isolates from the same area, with Scenedesmus flavescens (from Palandoken Teke Creek Pond) and Scenedesmus armatus (from Tortum Lake) serving as test species. The experiment spanned seven days, with daily measurements of cell counts and biomass, along with dry matter weight assessments at the start and end of the study. The results showed that S. armatus and S. flavescens achieved the highest biomass in co-culture with Bacillus sp. and Pseudomonas sp., the cell counts of S. armatus co-culture with Pseudomonas sp. (A5) were 306±16.21 cells/ml, and this group followed by A6 (251±13.37 cells/ml), A7 (260±17.6 cells/ml), and F8 (93±6.01 cells/ml) groups. In conclusion, 6% growth was detected in S. flavescens biomass and 7% in S. armatus biomass. MGPB bacteria enhanced the growth of microalgae, underscoring their potential for biotechnological applications.